1. Field of the Invention
The present invention generally relates to a wafer level module, and more particularly to a structure and fabricating method of a wafer level module with a solid adhesive film.
2. Description of Related Art
Wafer level optics is a technique of fabricating miniaturized optics such as lens modules or camera modules at the wafer level using semiconductor techniques. The wafer level optics technique is well adapted to mobile or handheld devices. In fabricating conventional wafer level optics, liquid adhesive is usually applied, for example, by screen printing or coating, between two substrates that are to be bonded. Owing to the characteristics of the liquid adhesive, the thickness of the resultant adhesive layer could not be maintained constant. Further, with reference to FIG. 1A and FIG. 1B, the liquid adhesive 10 may result in overflow between two substrates 12 and 14. In the worst case, the shift of the liquid adhesive may cause misalignment between the substrates, thereby malfunctioning the resultant module. Accordingly, the patterns of the module are commonly designed with larger margins, and thus fewer modules may be fabricated on a wafer. Moreover, a substantive portion of time is consumed in coating or printing the liquid adhesive, particularly to a module with complex patterns.
Due to the uneven thickness of the liquid adhesive as mentioned above, a wafer level lens module or camera module normally requires using additional adjustment means, such as a screw, in order to mechanically arrive at a required focus. For the foregoing reason that conventional wafer level modules cannot be effectively designed and fabricated, a need has arisen to propose a novel scheme for resolving the aforementioned drawbacks.